How to download file with puppeteer using headless: true?

Question

I've been running the following code in order to download a csv file from the website http://niftyindices.com/resources/holiday-calendar:

const puppeteer = require('puppeteer');

(async () => {
const browser = await puppeteer.launch({headless: true});
const page = await browser.newPage();

await page.goto('http://niftyindices.com/resources/holiday-calendar');
await page._client.send('Page.setDownloadBehavior', {behavior: 'allow', 
downloadPath: '/tmp'})
await page.click('#exportholidaycalender');
await page.waitFor(5000);
await browser.close();
})();

with headless: false it works, it downloads the file into /Users/user/Downloads. with headless: true it does NOT work.

I'm running this on a macOS Sierra (MacBook Pro) using puppeteer version 1.1.1 which pulls Chromium version 66.0.3347.0 into .local-chromium/ directory and used npm init and npm i --save puppeteer to set it up.

Any idea whats wrong?

Thanks in advance for your time and help,

Answer 1

This page downloads a csv by creating a comma delimited string and forcing the browser to download it by setting the data type like so

let uri = "data:text/csv;charset=utf-8," + encodeURIComponent(content);
window.open(uri, "Some CSV");

This on chrome opens a new tab.

You can tap into this event and physically download the contents into a file. Not sure if this is the best way but works well.

const browser = await puppeteer.launch({
  headless: true
});
browser.on('targetcreated', async (target) => {
    let s = target.url();
    //the test opens an about:blank to start - ignore this
    if (s == 'about:blank') {
        return;
    }
    //unencode the characters after removing the content type
    s = s.replace("data:text/csv;charset=utf-8,", "");
    //clean up string by unencoding the %xx
    ...
    fs.writeFile("/tmp/download.csv", s, function(err) {
        if(err) {
            console.log(err);
            return;
        }
        console.log("The file was saved!");
    }); 
});

const page = await browser.newPage();
.. open link ...
.. click on download link ..